Cheat menu:
Enter ALPUN as a code.

Cheat shop:
Enter LILBUDY as a code, then press Select + Up during game play.

Invincibility:
Enter MOLITOR as a code.

Level select:
Enter MBP4UJP as a code.

Unlimited ammunition:
Enter FALLOUT as a code.

Unlimited jet pack fuel:
Enter 38HK as a code.

Unlimited Mana:
Enter BGDA as a code.

Faster movement:
Enter THEHARE as a code.

Front view:
Enter XTRASEE as a code.

Close-ups:
Enter CLOSEUP as a code.

Front view when playing as Kabuto:
Enter KVIEW as a code.

Multi-color graphics:
Enter DOROTHY as a code.

Red graphics:
Enter ANGRY as a code.

Green graphics:
Enter SNIPEME as a code.

Blue graphics:
Enter UDDOIT2 as a code.

Hint: Vimp Souls:
In base missions while playing as Delphi, it is not necessary to hunt Vimps. You can also get soul energy from Sea Reapermen and the two kinds of Rippers that can burrow (but not the ones that approach the base along with the Reapermen.) In other words, you can hang around and defend your base while still powering the Persuader very nicely. With anything you kill, including Vimps, you must get close to the body before it disappears to get the soul energy (fairly easy, but a complete non-issue if you use the knife.) The soul gauge is located between the spell icons.